1. Field
Exemplary embodiments relate to near field lenses and imaging apparatuses including the same.
2. Description of the Related Art
Recently, following trends of technological acceleration, increasing integration, and miniaturization, demands for high sensitivity and high resolution for various measuring devices are increasing.
For example, research relating to resolving limits of resolution of optical microscopes has gained greater interest. An optical microscope for optically observing an object is unable to optically observe an object that is smaller than half a wavelength of a light irradiated onto the object.
A scattered light formed as a light collides with an object includes a near field light and a far field light. The near field light refers to a light that is unable to travel through a space and is localized on a surface of an object. A portion of a light irradiated onto an object and scattered by an object travels to a far field and forms an image via an optical lens, whereas the remaining part of the light stays near the object and disappears without transmitting any information. In case of an object smaller than about half a wavelength of a light, the major portion of a scattered light, which includes critical information for forming an image, is a near field light and stays near the object, and thus it is difficult to observe the object via an optical microscope.
Therefore, adjusting a near field light that stays near an object in order to facilitate travel thereof to a far field is the key to resolving a limit of resolution of an optical microscope.
A near field scanning optical microscopy (NSOM) equipment is widely used to embody a high resolution. A NSOM equipment scan-irradiates a near field light onto an object. The equipment is capable of scanning one point at a time, and thus there are limits to using the equipment with respect to a large area.
Furthermore, there is research relating to embodying a super lens that is capable of resolving a limit of resolution by using a meta-material. A meta-material is a material which exhibits optical properties that do not exist in nature and which has an artificial atomic structure including patterns of various shapes and subwavelength-order sizes. It is known that a meta-material may be used for subwavelength focusing with respect to electromagnetic waves, acoustic waves, and/or ultrasound waves. However, due to complicated structures, it is difficult to fabricate or utilize a meta-material.